The present invention relates to a method and an apparatus for producing vortex rings of a gas in a liquid for use in aquaria, fish farms, sewage disposal facilities and the like.
Conventionally, aquarium fish tanks, fish-farming ponds, and the like are provided with air or oxygen gas supply devices to produce spherical or medusoid bubbles in the water through nozzles and the like placed underwater for increasing or maintaining oxygen concentration in the water at a predetermined level and particularly in aquarium fish tanks for enjoyment purpose. However, in the conventional gas supply devices, dissolution of oxygen into water is not efficient for the amount of air or oxygen gas supplied and for the size of devices used. Furthermore, bubbles in the water do not provide much pleasure to spectators.